The invention relates to an extendable and retractable steering device of a two-track vehicle.
As the state of the art, in addition to DE 10 2006 006 995 A1, reference is made to WO 03/020571 A1.
In the (generally known) highly autonomous driving of a vehicle, a steering wheel (as the currently standard design of what is termed here a driver's steering handle) is not required. In this driving mode the steering wheel can be recessed into a so-called rest position in the vehicle's instrument panel, to free up space in the vehicle. The steering wheel, retracted in such a manner and therefore stored away relative to the usual extended usage position in which the driver steers the vehicle himself using the steering wheel, serves the additional function of a mode indicator for the autonomous driving mode.
The object of the present invention is to further develop a steering device such that the extension and retraction of the steering device is as comfortable as possible for the driver and, in particular, allows him as much free space as possible in the retracted rest position.
This and other objects are achieved by a steering device for a two-track vehicle, in particular a passenger car. The steering device can be moved between an extended (usage) position and a retracted (rest) position. In the extended position the steering device is used by the driver to steer the vehicle. In the retracted position, the steering device is recessed as far as possible into the instrument panel, in order to free up as much space as possible for the driver. In the retracted position the steering device cannot be used by the driver. If the steering device is located in the retracted position, the vehicle is either being controlled autonomously or is at a standstill. When at a standstill the retracted steering device offers the driver as much free space as possible when boarding and alighting from the vehicle.
The steering device according to the invention has a retaining element for the steering handle to be used by the driver in the usage position of the steering device. The retaining element is preferably concealed by an instrument panel of the vehicle both in the rest position and in the usage position, and is therefore not visible to the driver. The steering handle (for example in the form of a steering wheel or in the form of steering horns, also generally known) is arranged on the retaining element so that it can be rotated. This steering handle projects toward the driver, at least in the extended position. The driver can take hold of the steering handle, and thus steer the vehicle. In particular, a rod that is rotatably mounted in the retaining element is normally provided as a guide for the steering handle. The rod protrudes in the direction of the driver. At the end of the rod, the steering wheel or the steering horns is/are arranged. The steering device according to the invention is preferably intended for a (generally known) steer-by-wire (steering) system, so that no direct mechanical connection need be present between the steering handle and the steerable wheels of the vehicle.
The retaining element is displaceably mounted on a guide device, for example by way of rolling bearings or a friction bearing. The retaining element (and with it the steering handle), can be moved back and forth along this guide device between the retracted rest position of the steering device and its extended usage position.
If such a guide device extends only in the vehicle longitudinal direction, a relatively large amount of space must be reserved in the vehicle longitudinal direction to lower the steering handle as far as possible into the vehicle's instrument panel. It is therefore proposed according to the invention that the guide device extends both in the vehicle longitudinal direction and in the vehicle transverse direction. This means that when relocating into the retracted position, the steering handle moves at an angle to the vehicle longitudinal direction, and, for example, at least approximately in a horizontal plane. This allows a shift of the steering handle position which is comfortable for the driver, since it does not appear threatening, in particular when moving into the usage position, wherein this shift of position relative to the driver can take place quickly, i.e. in a very short time, which is very advantageous particularly in the event of termination of highly autonomous driving.
The steering device preferably comprises a drive for moving the retaining element along the guide device. In particular, the drive is an electric motor. The drive is preferably located on the retaining element. This means that a vehicle-fixed toothed rack can be provided. On the drive a pinion is then located, which engages with the toothed rack. The toothed rack preferably runs parallel to the guide device and can either be integrated into the guide device or arranged next to the guide device. As an alternative to a toothed rack, however, a belt drive can also be provided for relocating the steering handle with its retaining element.
Advantageously, the guide device has a curved shape. When retracting the steering device, the retaining element therefore follows a circular path, for example. As a result, the rod of the steering handle that is inserted in the retaining element is twisted relative to the vehicle longitudinal direction. This, in turn, leads to a very compact position of the steering handle with its retaining element in the retracted position. With the curved design of the guide device, other guides and drive elements, such as the above-mentioned toothed rack, are also preferably designed with a curved shape.
In any case, for a steer-by-wire steering system, a steering angle sensor and/or a steering torque sensor is provided on the retaining element. This sensor (or sensors) is used to detect a steering request applied by the driver to the steering handle. In addition, an actuator can be located on the retaining element, with which an actuating force can be exerted on the steering handle. Due to this actuating force the driver feels a corresponding resistance when steering, i.e. when specifying his steering request. The sensor(s) and actuator referred to can be integrated in a single assembly.
The motion of the steering device when relocating from the extended usage position into the retracted rest position (or vice versa) can be decomposed into a longitudinal component in the vehicle longitudinal direction and a transverse component in the vehicle transverse direction. Depending on the design of the guide device, a first length of the longitudinal component and a second length of the transverse component are obtained. For the most effective utilization of the available installation space, the following conditions are preferably proposed: the first length is preferably between 50% and 200%, in particular between 75% and 150%, of the second length. In particular, it is provided that the guide device is suitably curved within these specified values.
In the case of a steer-by-wire steering system, the vehicle can be steered with relatively small steering angles. Therefore, a steering wheel is not absolutely necessary here. Instead, it can be provided that the steering handle, as is generally known, comprises two steering horns positioned opposite one another (with respect to the rod that is rotatably mounted in the retaining element as referred to above). One steering horn is held by each of the driver's hands. Using the steering horns enables space to be saved, in particular in the direction of the vertical axis of the vehicle.
For a particularly space-saving arrangement of the steering device in the retracted position, it is preferably provided that the two steering horns are movable relative to one another. To achieve this, it is proposed that the steering handle comprises a linear steering horn guide. At least one of the steering horns is movable along this steering horn guide. It is thus possible to move the two steering horns toward each other when retracting the steering device. In a neutral position of the steering handle, the steering horn guide advantageously extends in the vehicle transverse direction.
A steering horn drive is preferably provided for moving at least one steering horn. In particular, the steering horn drive is an electric motor. Preferably, the steering horn drive is connected to one of the steering horns and is in engagement with a steering horn toothed rack via a pinion. Alternatively or in addition to the linear displacement of at least one steering horn, it is also possible that at least one of the steering horns can be folded down. This also enables a space-saving storage of the steering handle.
Extending from the vehicle or from an electrical energy distribution system of the vehicle and from a vehicle data bus, leads or cables are provided for the electrical energy transmission and information exchange with the steering device according to the invention and/or to the retaining element, in particular to sensors, actuator(s) and motor(s). These leads or cables are preferably held in a cable conduit. The cable conduit is preferably arranged such that it can pivot relative to the vehicle. When the retaining element for the steering handle is moved, the cable guide pivots along with it.
In terms of the arrangement of a steering device according to the invention with respect to a dashboard or instrument panel of the vehicle, the guide device and the retaining element are arranged behind the instrument panel, hence on the side of the instrument panel facing away from the driver. In the retracted position, the steering handle, possibly with the exception of the steering horns, is placed substantially within or behind the instrument panel. In the retracted position, a maximum of at least one of the steering horns protrudes some distance beyond the surface of the instrument panel in the direction of the driver. All other elements of the steering device are preferably recessed behind the instrument panel in the retracted position.
On the steering handle, for example in the center between the two steering horns, a control unit is preferably located. By pressing or touching this control unit, the retaining element with the steering handle moves into the retracted position. Preferably simultaneously with the touching or pressing, the control unit can change the vehicle into the autonomous driving mode. For example, the control unit can be integrated into an emblem of the vehicle manufacturer provided there.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.